Machine for welding together pieces of metal wire



March l, 1949. J. VAN DER WINDT 2,463,129

MACHINE FOR WELDING' TOGETHER PIECES OF METAL WIRE Filed July s, 194e il g @im-,M5-

Patented Mar. 1, 1949 MACHINE FOR WELDING TOGETHER PIECES OF METAL WIRE Jan van der Windt, Eindhoven, Netherlands, as-

signor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application July 3, 1946, Serial No. 681,178 In the Netherlands August 4, 1943 Section 1, Public Law .690, August 8, 1946 Patent .expires August 4, 1963 4 Claims.

This invention relates to the welding of metal Wire in end to end relationship with the aid of a condenser battery discharging across the wire ends to be joined. Welding of this type, socalled percussion Welding, is particularly suitable for connecting thin metal wires, such as used, for example, as supply wires for incandescent lamps and electronic tubes. Such a supply wire has an external portion, located outside the lamp vesu sel, a lead-through portion mostly sealed in glass, and an internal conducting wire. 'Ihese diierent wire portions must satisfy different mechanical and physical requirements, so that it is frequently advisable to use different materials for this purpose. As a lead-through wire through a glass wall molybdenum is desirable since this material permits a permanent gastight junction to be made in the glass wall. Outside the lamp copper wire can be used, while inside the lamp the use of nickel wire is sometimes desirable. Three pieces of wire of diierent materials can be joined together by means of an electric weld. However, the different materials impose different requirements as regards the current strength permissible. Consequently, it is customary to effect these welds in separate percussion-welding ma'- chines.

According to the invention, an important simplication of the manufacture of such composite wires is obtained by joining the pieces of wire in the same phase of operation, but establishing the different welded joints one after the other with the aid of discharges of different batteries of condensers. On the one hand, an irmportant economy of time is thus obtained, since the three pieces of wire are now joined together in the same welding machine. At the same time, the diierent requirements as regards the strength of the welding current can be met, since separate batteries of condensers are used for the different welds.

The wire welding machine of the invention is characterized by two separate electric circuits, each including a battery of condensers, these batteries having one pole in common and their other two poles electrically separated. The common pole is connected to the pinch or support for the middle piece of the three pieces of wire to be joined. Each of the two separate poles is connected to one of the two other wire ends, f

which are initially electrically insulated from each other. As the two welds are not obtained at the same time, but one after the other, the current strength through the first weld will be solely determined, when making this weld, by the disof the lamp.

charge of the battery of condensers connected in parallel to it. The charge of the other battery of condensers is also connected to this weld on one side, it is true, but the other side is insulated therefrom. When making the second weld, the first battery of condensers is discharged and short-circuited by the rst weld, so that this cannot act upon the second weld.

In order that the invention may be clearly understood and readily carried into effect, it will now be explained more fully with reference to the accompanying drawing.

Fig. 1 shows, partly diagrammatically, the construction of the support for the three pieces of wire.

Fig, 2 is the circuit diagram of the two halves oi the Welding apparatus.

In Fig. l, I0 and II designate the two outer pieces of wire which constitute, for example in an incandescent lamp, the connecting wire outside the bulb and the supply wire inside the bulb respectively. In between these two pieces there must be welded a short wire I2 which must be established in a gas-tight manner in the walls In the wire-welding machine these three pieces of wire are held in three different holders I3, I4 and I5, which are electrically insulated from one another and of which the holder I5 has a xed position in the machine; the holders I3 and I4 pivoted in points I8 can, however, be moved to and fro under the inuence of two cam discs I6 and I1, which are arranged on the same driving shaft I9, but with such a relative phase shift that at Iirst the holder I3 is moved towards the holder I5 and only then the holder I4. The holders I 3, I4, and I5 are included in the two electric circuits of the welding apparatus shown in Fig. 2. These two circuits are substantially constituted by two batteries of condensers 2U and 2| which can be charged from a common source 22 of direct current, in this case a rectier connected to three-phase current mains. This charge is effected periodically some time after the two preceding welds have been made, since on the same shaft I9, having cam discs I6 and Il, there is arranged a switch 23 by which during a short time the two batteries of condensers are connected in parallel to the source 22 of direct current with the interposition of current limiting resistances 2'! and 24 respec tively. After the batteries of condensers have been charged, but before the welding has set in, the switch 23 re-opens, in orderto prevent the rectifier from lsending current through the weld to be made.

and .-31

Between the source of direct current and each battery of condensers there are provided reversing switches 28 and 25 respectively. This permits the direction in which the condensers are charged to be reversed and consequently the -direction of current, when making the weld, to be established as desired. In fact, with sonne combinations of metals the weld is realized rbetter if one metal only forms the positive pole of the weld, but in the case of a combination of one of these metals with another metal a ydifferent `direction of current may be desirable. The `strength of the welding current may be controlled for the two welds in common by an increase or ra, reduction of the voltage of the rectiiier '22. voltage of the battery of condensers 2D can further be controlled separately lwith fthe aid of the potentiometer 34. The variation of the current flowing through each weld can be controlled separately with the aid of variable resistances 3S respectively. The current strength through each weld, too, can be controlled by varying the capacity of each of the batteries of condensers separately.

The two electric circuits,-each of which com# yprises a battery of condensers, have 4one pole in common, i. e. that side of the batteries vof condensers which vis connected to the holder I5. The other poles of the .two `batteries `of convdensers are .electrically separated from each other ywhen the charge has finished and the switch 23 has re-opened. These two poles rare connectedto the holders .I3 and I4 respectively.

.First the holder I3 approaches 'the holder I5,

and the Weld between the wires iii and I-2 is made, then by 'a similar movement of the holder I4, the weld between 'the wires H v'and II2 is established. The two circuits/ and 21 will not act electrically upon each other, since their parallel connection-on thefside ofthe rectifier is interrupted ybefore the manufacture of the iirst weld begins due to the `presence of a set of switches 33 between each condenser circuit and the .-rectien These switches are also opened by the'shaft .IQof the machine before the welding ,f .has started and are closed again after the welding tis completed. Consequently, 'the two welds are made independently of each other, and the `conditions foreach vof these -welds can be fuljlled independently of each other.

What I claim is: i. An .arrangement for vforming 'a weld between one end of afirst wire androne end of ia second =wire anda weld between the other end :of said rst wire vand one end of a third wire comprising, a first storage capacitance, a second :storage capacitance, a first resistance, a second resistance, each of said storage capacitances having one rend Vconnected .in common 'with said first wire, the other end 'off said first Ystorage capacitance being 'fconn'ected to fsaid second wire Athrough .said first resistance, Athe vother end vof Isaid second storage capacitance 'being connected to said third wire through said second resistance,

Va voltage source for charging said storage capacitances, said voltage source being connected to said storage capacitances in parallel,

switch means operative to disconnect said voltage source from 'said storage capacitances,

second wires and to advance said third-'wire lto The 4 contact said rst wire to discharge said second storage capacitance and form a weld between said rst and third wires.

2. An arrangement for forming la weld between one end of a rst wire and one Vend of a second wire and a weld between the other end of said rst wire and one end of a third wire comprising, a yfirst storage capacitance, a second storage capacitance, a irst resistance, a second resistance, each of said storage capacitances havvin-gone end connected in common with said first wire, the other end of said first storage capacitance being connected to said second wire through said rst resistance, the other end of said Vsecondstorage capacitance being connected to said third wire through said second resistance, a voltage source for charging said storage capacitance, said voltage source being connected to `said storage capacitances in parallel, means to reverse the polarity of said voltage source as applied to said storage capacitances, switch 'means to disconnect said voltage source from said storage capacitances, and means adapted .in a rst position to operate said switch means and in a second position to successively advance said second wire to contact said rst wire to discharge `said rst storage capacitance and form a welded connection between 'said rst and second wires and to advance said third vwire to contact said .rst wire to discharge said second storage capacitance and form a welded connection between said rst and third wire.

3. An arrangement for forming a weld between one end of 'a rst wire and one end of a second wire and a weld between the other end of said first wire and one end of a third wire comprising,

`a rst storage cap-acitance, a second storage .ca-

pacitance, a rst resistance, a `second resistance, each of -said storage `capacitances having one end connected in common with said first wire, the other lend of said first storage capacitance being connected to said second wire through said iirst resistance, the other end of said second storage capacitance being connected to said third wire through said second resistance, a voltage source for charging said storage capacitances, said voltage source being connected to said storage -capacitances -in parallel, means to independently regulate the magnitude of charge of each of said storage capacitances, switch means to disconnect said voltage source from said storage capacitance, and means adapted in a rst position to -operate said switch means and in a :second position to successively advance said second wire to contact said first 'wire to discharge said vfirst storage capacitance and form a welded connection between said first and second wires, and to advance said third wire to contact said rst lwire to ldischarge .said second storage capacitance and form a welded connection between said rst land `said third wires.

4. An arrangement 'for forming a 'weld -between `one end of a iirst -wire and one end of a age condensers having one end :connected in common with said iirst wire, the :other end ofisaid Vfirst battery of storage condensers connected .to

said second wire through said first rheostat, the other :end Aof lsaid Isecond battery "of storage 'con- -densers conn'ect-ed't'o said thi-rd wire through said.

second rheostat, a voltage source for charging said batteries of storage condensers, said voltage source being connected to said batteries of storage condensers in parallel, a first switching means to reverse the polarity of said voltage source as applied to said batteries of storage condensers, a resistance means to independently regulate the magnitude of charge of each of said batteries of storage condensers, a second switching means operative to disconnect said voltage source from said batteries of storage condensers, and cam means adapted in a rst position to operate said second switching means and in a second position to successively advance said second wire to contact said rst wire to discharge said rst battery of storage condensers and form a welded connection between said first and second wires and to advance said third wire to contact said rst wire to discharge said second battery of storage condensers and form a Welded connection between said rst and third wires.

JAN VAN DER WINDT.

5 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

